A wide variety of semi-synthetic cephalosporins have been prepared and tested since the natural group of cephalosporins were discovered. A most difficult problem within this area is the discovery of cephalosporins which are effective when administered orally. Cephaloglycine, U.S. Pat. No. 3,560,489; cephalexin, U.S. Pat. No. 3,507,861; and cephradine, U.S. Pat. No. 3,485,819 are the only compounds that have had sufficient oral activity to warrant commercial use. We have now discovered a new series of cephalosporins which have oral activity.
The prior art includes U.S. Pat. No. 3,464,985 which discloses compounds with a lower alkanoylamino group substituted at any position on the phenyl ring of cephaloglycine. Also disclosed are similar compounds where the amino and amido nitrogen atoms of the above compounds have been reacted with acetone to give a cyclic system. U.S. Pat. No. 3,634,418 discloses 3-azidomethylcephalosporins containing a lower alkanoylaminophenylglycyl group at position 7. Other cephalosporins containing an alkanoylaminophenyl group are described in U.S. Pat. No. 3,646,024. Phenylglycylcephalosporins having a 3-heterocyclicthiomethyl group are described in U.S. Pat. Nos. 3,641,021; 3,687,948; 3,759,904; 3,757,012; 3,743,644; 3,734,907; and perhaps others which are unknown to me at this time.